Seeds used in brachytherapy, a prostate cancer treatment that often follows hormone therapy. (Gary Friedman/Los Angeles Times via Getty Images)

Black men treated with hormone therapy for prostate cancer may have a higher risk of death than white men undergoing the same therapy, according to a new study. But the deaths aren’t actually caused by prostate cancer.

Androgen deprivation therapy, or ADT, is a hormone treatment that shrinks prostate tumors. Researchers from the Brigham and Women’s Hospital in Boston found that black men undergoing the therapy had a 77 percent higher risk of death than non-black men.

Researchers at Brigham and Women's Hospital looked through medical records of about 1,500 men from the Chicago Prostate Cancer Center with low- or intermediate-risk prostate cancer who were treated with ADT. About 7 percent were black.

The small study, in the journal Cancer, found that black men were usually younger, treated later and more likely to have other health issues.

Black men had a higher incidence of death after only four months of hormone therapy, the researchers found, but none of the causes of death in the study were actually prostate cancer.

Konstantin Kovtun, one of the lead researchers for the study, said the deaths seem to be related to cardiovascular health issues that existed prior to a cancer diagnosis. “African American men have an onset of cardiovascular problems that are linked to ADT use,” he said.

The study noted that earlier research has found shorter survival rates among intermediate- to high-risk prostate cancer patients using ADT because of an increased risk in fatal heart attack.

Jonathan Simons, president and chief executive officer of the Prostate Cancer Foundation, said the study was interesting but needs to be followed by more research, including a closer examination of the causes of death. “We don’t know the real reason for the number of deaths," he said.

Black men typically fare worse with prostate cancer than white men, Simons said, and the reasons for the differences are understudied and poorly understood.

“You can have a man of European and a man of African descent,” he said. “Even if they get the same health care, insurance and doctors, black men still have it worse with prostate cancer.”

Kovtun hopes that the study helps inform decisions about treatment.

“If I was a physician and I had the data now available for the study, I would be more careful in using ADT for African American men,” he said.